Temperature-sensitive fire detector and detection alarm method thereof

Abstract

The invention provides a temperature sensing fire detector. The temperature sensing fire detector is mainly composed of a sheet-shaped temperature sensing element, a signal processing unit and a plurality of connecting wires between the sheet-shaped temperature sensing element and the signal processing unit. Wherein the sheet-shaped temperature sensitive element comprises a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistance material between the longitudinal conductor group and the transverse conductor group, the longitudinal conductor group is composed of a plurality of longitudinal conductors which are arranged in parallel at intervals, and the transverse conductor group is composed of a plurality of transverse conductors which are arranged in parallel at intervals; the plurality of longitudinal conductors and the plurality of transverse conductors are perpendicular to each other; the fire detection coverage area is wide; a negative temperature coefficient material is adopted for detection, and physical short-circuit faults and heated short-circuit fire alarms can be distinguished; according to the invention, the position of a temperature measuring point in a two-dimensional space and a three-dimensional space and the position of a fire source in the two-dimensional space and the three-dimensional space can be accurately positioned, and real-time temperature Multi-point temperature measurement can be realized, and temperature field data on the whole sheet-shaped detector can be constructed.

Description

Technical Field

[0001] The present invention belongs to the technical field of fire detection, and relates to a temperature-sensitive fire detector and a detection and alarm method thereof, and in particular to a temperature-sensitive fire detector capable of detecting surface monitoring objects (such as all power cables in the entire power cable bridge) and a detection and alarm method thereof. Background Art

[0002] The existing cable-type linear heat-sensing fire detector can continuously detect the temperature change at any point along the installation length of its temperature-sensitive element (ie, the temperature-sensitive cable), but the limitation is that the temperature-sensitive element is only concentrated on one cable.

[0003] Regarding the existing cable-type linear temperature-sensitive fire detector, Chinese patent CN202010459295, which is named a wide mesh fire detector, discloses a wide mesh fire detector, which is composed of multiple elastic metal conductors coated with a fusible insulating material layer as longitudinal conductors, and an elastic metal conductor coated with a fusible insulating material layer as a transverse conductor. The transverse conductors and the longitudinal conductors are woven into a mesh structure in an alternating manner, and the two ends of the longitudinal conductor of the mesh structure are respectively connected together, and finally the two ends of the transverse conductor and the two ends of the longitudinal conductor after the line is collected are respectively connected to the conversion box and the open-circuit detection resistor, so as to form a multi-point wide mesh fire detector in a plane. The detector of this patent can monitor the changes of fire in the detection area with 100% coverage, which overcomes the defect that the existing linear temperature-sensitive fire detection can only detect a very small range around the extension body. However, the following problems still exist: 1) The above wide mesh fire detectors are still in the switch detection mode in principle (i.e., by detecting the terminal resistance R to determine whether there is a short circuit or open circuit in the circuit, and thus determine the fire alarm or fault). They cannot distinguish between normal temperature rise short circuit and short circuit caused by physical factors such as squeezing and pulling between horizontal and vertical conductors, which may lead to false fire alarms. 2) The weaving process of the above-mentioned wide mesh fire detector is complicated, which may cause the insulation material wrapped outside the wire core to be squeezed and ruptured; 3) The above wide mesh fire detectors cannot locate the specific location of the fire, and cannot determine the temperature change trend or temperature rise rate of the surface of the monitored object. Summary of the invention

[0004] Based on the above problems, the purpose of the present invention is to provide a temperature-sensitive fire detector with reliable fire alarm, fire location positioning, and monitoring of the temperature change trend or temperature rise rate of the surface of an object; mainly composed of a sheet-shaped temperature sensitive element and a signal processing unit and a plurality of connecting wires therebetween; wherein the sheet-shaped temperature sensitive element includes a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistor material therebetween, the longitudinal conductor group is composed of a plurality of longitudinal conductors arranged in parallel at intervals, the transverse conductor group is composed of a plurality of transverse conductors arranged in parallel at intervals, and the plurality of longitudinal conductors and the transverse conductors are perpendicular to each other; The plurality of connecting wires include a plurality of longitudinal connecting wires and a plurality of transverse connecting wires; the signal processing unit is mainly composed of a processor, a sampling controller, an electronic switch group and an output actuator; the electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a plurality of transverse normally-open electronic switches; one end of the plurality of longitudinal conductors and one end of the plurality of transverse conductors are respectively connected to the plurality of longitudinal normally-open electronic switches and the plurality of transverse normally-open electronic switches through a plurality of longitudinal connecting wires and a plurality of transverse connecting wires in a one-to-one correspondence, and then electrically connected to the processor through the sampling controller; the output actuator is electrically connected to the processor.

[0005] The present invention provides another temperature-sensitive fire detector, which is mainly composed of a sheet-shaped temperature sensitive element and a signal processing unit and a plurality of connecting wires therebetween; wherein the sheet-shaped temperature sensitive element comprises a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistance material therebetween; the longitudinal conductor group is composed of a plurality of longitudinal conductors arranged in parallel at intervals; the transverse conductor group is composed of a plurality of transverse conductors arranged in parallel at intervals, and the plurality of longitudinal conductors and the transverse conductors are perpendicular to each other; the plurality of connecting wires comprises a transverse connecting wire and a plurality of longitudinal connecting wires; the signal processing unit is mainly composed of a processor, a sampling controller, an electronic switch group and an output actuator; the electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a transverse normally-open electronic switch; the left and right ends of the plurality of transverse conductors are connected at intervals to form a serpentine transverse conductor, and one end of the plurality of transverse conductors is connected to the transverse normally-open electronic switch through the transverse connecting wire; one end of the plurality of longitudinal conductors is connected to the plurality of longitudinal normally-open electronic switches one by one through the plurality of longitudinal connecting wires, and then electrically connected to the processor through the sampling controller; the output actuator is electrically connected to the processor.

[0006] In the above-mentioned temperature-sensitive fire detector, preferably, the negative temperature coefficient resistance material constitutes a sheet, the longitudinal conductor group and the transverse conductor group are respectively laid on the upper and lower surfaces of the sheet, and the projections of the plurality of longitudinal conductors and transverse conductors on the surface of the sheet are perpendicular to each other.

[0007] In the above-mentioned temperature-sensitive fire detector, preferably, the negative temperature coefficient resistance material is coated outside the plurality of longitudinal conductors and / or the plurality of transverse conductors, and the plurality of longitudinal conductors and transverse conductors are woven or layered up and down into a mutually perpendicular mesh structure.

[0008] In the above-mentioned temperature-sensitive fire detector, preferably, the plurality of longitudinal conductors and the plurality of transverse conductors are respectively made of two different types of metal materials.

[0009] In the above-mentioned temperature-sensitive fire detector, preferably, the outer side of the sheet-shaped temperature sensitive element is also covered with a waterproof insulating protective layer.

[0010] The present invention provides a detection alarm method, the method comprising: Step 1: The sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one horizontal conductor in the sheet-like temperature sensitive element to close, and respectively measures the resistance value between the vertical conductor X1 and the horizontal conductor; Step 2: Following step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to the at least one horizontal conductor in the sheet-shaped temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one of the remaining horizontal conductors in the sheet-shaped temperature sensitive element is closed; and at the same time, the resistance value between the longitudinal conductor X1 and the longitudinal conductor X1 is measured respectively; Step 3: Follow step 2 until the resistance values ​​between the longitudinal conductor X1 in the sheet-shaped temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; Step 4: Following step 3, after a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the resistance values ​​between the vertical conductor X2 in the sheet-like temperature sensitive element and all the transverse conductors in turn using the same method as steps 1 to 3; Step 5: Following step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as steps 1 to 4 is used until the resistance values ​​between the longitudinal conductor Xn in the sheet-like temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; that is, one measurement cycle is completed; Step 6: Continue with step 5, and repeat the measurement from step 1 to step 5 over and over again; The sampling controller in steps 1 to 6 respectively measures the resistance value in real time and sends it to the processor connected thereto in real time. The processor compares the resistance value with the resistance value corresponding to the preset temperature alarm threshold in real time to determine whether it is a fire alarm, and directly outputs a fixed temperature alarm signal through the output actuator connected to the processor, or calculates whether the temperature change rate per unit time reaches the preset differential temperature alarm threshold, and the output actuator outputs a differential temperature alarm signal; The sheet-shaped temperature sensitive element comprises a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistor material therebetween, wherein the longitudinal conductor group is composed of a plurality of longitudinal conductors X1, X3, ..., Xn which are fixedly spaced and parallel, and the transverse conductor group is composed of a plurality of transverse conductors Y1, Y2, ..., Yn which are fixedly spaced and parallel, and the projections of the plurality of longitudinal conductors and the transverse conductors on the surface of the sheet-shaped body are perpendicular to each other; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a plurality of transverse normally-open electronic switches; one end of the plurality of longitudinal conductors and one end of the plurality of transverse conductors are connected to the plurality of longitudinal normally-open electronic switches and the plurality of transverse normally-open electronic switches in a one-to-one correspondence through a plurality of longitudinal connecting wires and a plurality of transverse connecting wires, respectively.

[0011] The detection alarm method described above is preferably: The step 1: the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-like temperature sensitive element to close and measure the resistance value between the vertical conductor X1 and the horizontal conductor Y1; The step 2 is as follows from the step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-like temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y2 in the sheet-like temperature sensitive element is closed; and the resistance value between the longitudinal conductor X1 and the horizontal conductor Y2 is measured at the same time; Step 3: Following step 2, the transverse conductors Y3, ..., Yn in the sheet-like temperature sensitive element are measured in sequence, until the resistance value between the longitudinal conductor X1 and the transverse conductor Yn in the sheet-like temperature sensitive element is measured; The step 4 is as follows from the step 3. After a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the resistance values ​​between the vertical conductor X2 and the horizontal conductors Y1, Y2, ..., Yn in the sheet-like temperature sensitive element in the same manner as the steps 1 to 3; The step 5: following the step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as the steps 1 to 4 is used until the resistance value between the longitudinal conductor Xn and the transverse conductors Y1, Y2, ..., Yn in the sheet-like temperature sensitive element is measured; that is, one measurement cycle is completed; The step 6 is followed by the step 5, and the steps 1 to 5 are repeated and measured over and over again.

[0012] The detection alarm method described above is preferably: In the steps 1, 2 and 3, the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-shaped temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to a serpentine horizontal conductor in the sheet-shaped temperature sensitive element to close and measure the resistance value between the vertical conductor X1 and the serpentine horizontal conductor; The step 4 is as follows from the steps 1, 2 and 3. After a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the resistance value between the vertical conductor X2 in the sheet-like temperature sensitive element and the serpentine transverse conductor in turn respectively by the same method as the steps 1, 2 and 3; The step 5: following the step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, using the same method as the steps 1, 2 and 3 to step 4 until the resistance value between the longitudinal conductor Xn in the sheet-like temperature sensitive element and the serpentine transverse conductor is measured; that is, one measurement cycle is completed; Step 6: Continuing from step 5, repeat the measurement from steps 1, 2 and 3 to step 5, and repeat the process over and over again; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a transverse normally-open electronic switch; the serpentine transverse conductor is composed of a plurality of transverse conductors whose left and right ends are connected at intervals, and one end of the serpentine transverse conductor is connected to the transverse normally-open electronic switch through the transverse connecting wire; one end of the plurality of longitudinal conductors is respectively connected to the plurality of longitudinal normally-open electronic switches one by one through a plurality of longitudinal connecting wires.

[0013] The present invention provides another detection alarm method, the method comprising: Step 1: The sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one horizontal conductor in the sheet-like temperature sensitive element to close and respectively measure the voltage value between the vertical conductor X1 and it; Step 2: Following step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one horizontal conductor in the sheet-shaped temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one of the remaining horizontal conductors in the sheet-shaped temperature sensitive element is closed; and at the same time, the voltage value between the longitudinal conductor X1 and it is measured respectively; Step 3: Follow step 2 until the voltage values ​​between the longitudinal conductor X1 in the sheet-shaped temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; Step 4: Following step 3, after a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the voltage values ​​between the vertical conductor X2 in the sheet-like temperature sensitive element and all the transverse conductors in turn using the same method as steps 1 to 3; Step 5: Following step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as steps 1 to 4 is used until the voltage values ​​between the longitudinal conductor Xn in the sheet-like temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; that is, one measurement cycle is completed; Step 6: Continue with step 5, and repeat the measurement from step 1 to step 5 over and over again; The sampling controller in steps 1 to 6 respectively measures the voltage value in real time and sends it to the processor connected thereto in real time. The processor compares its resistance value with the voltage value corresponding to the preset temperature alarm threshold in real time to determine whether it is a fire alarm, and directly outputs a fixed temperature alarm signal through the output actuator connected to the processor, or calculates whether the temperature change rate per unit time reaches the preset differential temperature alarm threshold, and the output actuator outputs a differential temperature alarm signal; The sheet-shaped temperature sensitive element comprises a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistor material therebetween, the longitudinal conductor group is composed of a plurality of longitudinal conductors X1, X3, ..., Xn which are fixedly spaced and parallel, the transverse conductor group is composed of a plurality of transverse conductors Y1, Y2, ..., Yn which are fixedly spaced and parallel, and the projections of the plurality of longitudinal conductors and the transverse conductors on the surface of the sheet body are perpendicular to each other; the plurality of longitudinal conductors X1, X3, ..., Xn and the plurality of transverse conductors Y1, Y2, ..., Yn are respectively made of two different kinds of metal materials; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a plurality of transverse normally-open electronic switches; one end of the plurality of longitudinal conductors and one end of the plurality of transverse conductors are connected to the plurality of longitudinal normally-open electronic switches and the plurality of transverse normally-open electronic switches in a one-to-one correspondence through a plurality of longitudinal connecting wires and a plurality of transverse connecting wires, respectively.

[0014] The detection alarm method described above is preferably: In step 1, the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-shaped temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-shaped temperature sensitive element to close and measure the voltage value between the vertical conductor X1 and the horizontal conductor Y1; The step 2 is as follows from the step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-like temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y2 in the sheet-like temperature sensitive element is closed; and the voltage value between the longitudinal conductor X1 and the horizontal conductor Y2 is measured at the same time; The step 3: following the step 2, the transverse conductors Y3, ..., Yn in the sheet-like temperature sensitive element are measured in sequence, until the voltage value between the longitudinal conductor X1 and the transverse conductor Yn in the sheet-like temperature sensitive element is measured; The step 4 is as follows from the step 3. After a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the voltage values ​​between the vertical conductor X2 in the sheet-like temperature sensitive element and the horizontal conductors Y1, Y2, ..., Yn in turn respectively by using the same method as the steps 1 to 3; Step 5: Following step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as steps 1 to 4 is used until the voltage value between the longitudinal conductor Xn and the transverse conductors Y1, Y2, ..., Yn in the sheet-like temperature sensitive element is measured; that is, one measurement cycle is completed; The step 6 is followed by the step 5, and the steps 1 to 5 are repeated and measured over and over again.

[0015] The detection alarm method described above is preferably: In the steps 1, 2 and 3, the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to a serpentine horizontal conductor in the sheet-like temperature sensitive element to close and measure the voltage value between the vertical conductor X1 and the serpentine horizontal conductor; The step 4 is as follows: following the steps 1, 2 and 3, after a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the voltage value between the vertical conductor X2 in the sheet-like temperature sensitive element and the serpentine transverse conductor in turn respectively by the same method as the steps 1, 2 and 3; The step 5: following the step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, using the same method as the steps 1, 2 and 3 to step 4 until the voltage value between the longitudinal conductor Xn in the sheet-like temperature sensitive element and the serpentine transverse conductor is measured; that is, one measurement cycle is completed; Step 6: Continuing from step 5, repeat the measurement from steps 1, 2 and 3 to step 5, and repeat the process over and over again; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a transverse normally-open electronic switch; the serpentine transverse conductor is composed of a plurality of transverse conductors whose left and right ends are connected at intervals, and one end of the serpentine transverse conductor is connected to the transverse normally-open electronic switch through the transverse connecting wire; one end of the plurality of longitudinal conductors is respectively connected to the plurality of longitudinal normally-open electronic switches one by one through a plurality of longitudinal connecting wires.

[0016] In the detection and alarm method described above, preferably, the sheet body is made of negative temperature coefficient resistance material, the longitudinal conductor group and the transverse conductor group are respectively laid on the upper and lower surfaces of the sheet body, and the projections of the plurality of longitudinal conductors and transverse conductors on the surface of the sheet body are perpendicular to each other.

[0017] In the detection alarm method described above, preferably, the negative temperature coefficient resistance material is coated outside the plurality of longitudinal conductors and / or the plurality of transverse conductors, and the plurality of longitudinal conductors and transverse conductors are woven or layered up and down into a mutually perpendicular mesh structure.

[0018] In the above-mentioned detection alarm method, preferably, a waterproof insulating protective layer is also covered on the outer sides of the longitudinal conductor group and the transverse conductor group.

[0019] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0020] 1. Compared with the cable-type temperature sensing detectors in the prior art, the temperature sensing detection coverage area of ​​the detector of the present invention is wide; especially compared with the cable-type temperature sensing detectors with parallel negative temperature coefficient characteristics in the prior art, the detector of the present invention can completely overcome the previous difficulty in distinguishing the resistance drop caused by a small increase in temperature over a long distance of the thermistor from the resistance drop caused by local high temperature, thereby improving the accuracy of the detector's fire alarm.

[0021] 2. Compared with the existing mesh detectors, the present invention uses negative temperature coefficient resistance material detection (i.e., detecting the change of the resistance value of the thermal insulation material with temperature), which can distinguish between physical short circuit faults and thermal short circuit fire alarms; 3. Whether compared with the cable-type temperature sensing detectors of the prior art or the mesh detectors of the prior art, the present invention can accurately locate the temperature measuring points in two-dimensional and three-dimensional space and the fire sources in two-dimensional and three-dimensional space, and display real-time temperature values; it can realize multi-point temperature measurement on the sheet detector, and construct the temperature field data on the entire sheet detector through the returned multi-point measurement values; it can not only realize fixed temperature alarm, but also realize differential temperature alarm by calculating the temperature rise rate; there is no need for external terminal resistance to form a loop. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structural principle of a heat-sensing fire detector provided in Example 1; Figure 2 yes Figure 1 A schematic diagram of the three-dimensional structure of the sheet-like temperature sensitive element 6 shown in FIG. Figure 3 yes Figure 1 A schematic diagram of the temperature measuring point thermistor area division structure of the sheet-shaped temperature sensitive element 6 shown in FIG. Figure 4 It is a three-dimensional perspective view of a sleeve-shaped sheet-shaped temperature sensitive element provided by the present invention; Figure 5 yes Figure 4 A cross-sectional view of a sleeve-shaped sheet temperature sensing element is shown.

[0023] Unified description of the numbers in the accompanying drawings: 1. Signal processing unit, 2. Processor, 3. Output actuator, 4. Sampling controller, 5. Electronic switch group, 6. Sheet temperature sensitive element, 7. Longitudinal conductor group, 8. Transverse conductor group, 7', radial conductor group, 8' / Y', axial conductor, 9. Connecting wire, 10. Sheet body, 11. Waterproof insulation protective layer, 15. Power cable or heating pipeline; X1, X2, X3...Xn are several longitudinal conductors respectively; Y1, Y2, Y3...Yn are several transverse conductors respectively; X1', X2', ..., Xn' are several radial conductors respectively. DETAILED DESCRIPTION

[0024] A temperature-sensitive fire detector and an alarm method thereof provided by the present invention are described in detail below in conjunction with the accompanying drawings and embodiments. Embodiment 1

[0025] The temperature-sensitive fire detector provided in this embodiment is mainly composed of a sheet-shaped temperature sensitive element 6 and a signal processing unit 1 and a plurality of connecting wires 9 therebetween. (The plurality of connecting wires 9 include a plurality of longitudinal connecting wires and a plurality of transverse connecting wires, or a transverse connecting wire and a plurality of longitudinal connecting wires) The sheet-shaped temperature sensitive element 6 comprises a sheet-shaped body 10 with a certain thickness formed of a negative temperature coefficient resistance material, a longitudinal conductor group 7 and a transverse conductor group 8 respectively laid on the upper and lower surfaces of the sheet-shaped body 10 in the thickness direction (or embedded to a certain depth) and evenly spaced, and a waterproof insulating protective layer 11 covering the sheet-shaped body 10 and the outer sides of the longitudinal conductor group 7 and the transverse conductor group 8, wherein the projections of the longitudinal conductor group 7 and the transverse conductor group 8 on the surface of the sheet-shaped body are perpendicular to each other. The various parts of the sheet-shaped temperature sensitive element 6 are tightly stacked together through a pressing process, and the overall edge is sealed by means of gluing (the longitudinal conductor group 7 and the transverse conductor group 8 should be appropriately extended from the sheet-shaped body 10 for easy wiring), and finally a sheet-shaped thermal sensitive element that is waterproof, moisture-proof and mechanically damage-proof is formed.

[0026] The signal processing unit 1 is composed of a processor 2, a sampling controller 4, an electronic switch group 5, an output actuator 3 (which can be an indicator light, a relay, etc.), and necessary protective housings and wiring terminals. The electronic switch group 5 is mainly composed of a number of horizontal normally open electronic switches and a number of vertical normally open electronic switches (which can be relays, triodes, etc.), and is connected to the vertical conductor group 7 and the horizontal conductor group 8 in the above-mentioned sheet-shaped temperature sensitive element 6 through a number of connecting wires 9; the sampling controller 4 can control the individual opening and closing of each of the above-mentioned electronic switches, and ensure that only one vertical conductor in the vertical conductor group 7 and one horizontal conductor in the horizontal conductor group 8 are connected at any time, and measure the insulation resistance Rt between the two connected vertical and horizontal conductors in real time. The processor 2 is connected to the sampling controller 4, and receives the insulation resistance Rt measured by it in real time, compares it with the preset temperature alarm threshold, so as to judge the fire alarm situation, and controls the output actuator 3 to output a fixed temperature alarm through a preset program, or realizes the differential temperature alarm output by calculating whether the temperature change rate per unit time reaches the differential temperature alarm threshold. Obviously, the processor 2 can output the position of the alarm point while giving an alarm by the position of the electronic switch that is opened and closed independently.

[0027] Here’s how it works: For the convenience of description, the numbering of the plurality of longitudinal conductors in the longitudinal conductor group 7 is respectively X1, X2, X3 ... Xn from left to right, and the numbering of the plurality of transverse conductors in the transverse conductor group 8 is respectively Y1, Y2, Y3 ... Yn from top to bottom. The sampling controller 4 sequentially controls the electronic switch connected to the longitudinal conductor X1 to close, and then controls the electronic switch connected to the transverse conductor Y1 to close and measure the resistance value between the longitudinal conductor X1 and the transverse conductor Y1, and after a preset time interval, the electronic switch connected to the transverse conductor Y1 is disconnected again, and the electronic switch connected to the transverse conductor Y2 is closed to measure the resistance value between the longitudinal conductor X1 and the transverse conductor Y2, and this sequence is followed until the resistance value between the longitudinal conductor X1 and the transverse conductor Yn is measured. Then after a preset time, the sampling controller 4 disconnects the electronic switch connected to the longitudinal conductor X1 and closes the electronic switch connected to the longitudinal conductor X2, and measures the resistance values ​​between the longitudinal conductor X2 and the transverse conductors Y1, Y2...Yn in turn in the same process as before. According to this rule, a cycle of temperature measurement of the intersection positions of all conductor groups within the installation range of the sheet body is completed, and the cycle is repeated.

[0028] In actual application, the sheet temperature sensitive element is laid on the surface of the protected object, and the sheet temperature fire detector is put into a quasi-working state by powering on. When the protected object is initially on fire, the temperature rises in a small area, which can be regarded as a local point fire source. Since thermistors have the characteristic that the resistance value changes sharply when the temperature rises (for the convenience of analysis, negative temperature coefficient resistor materials (i.e., the resistance value drops sharply when the temperature rises, referred to as NTC or thermistor materials or thermistor elements) are used as an example), the real-time resistance value between the upper and lower surfaces of the sheet body at a local position affected by the fire source decreases sharply. Assuming that the conductors passing through this local area are the longitudinal conductor Xn and the transverse conductor Yn, the local thermistor affected by the fire source is Figure 3 The volume resistance value Rre of the rectangular block corresponding to the colored area on the upper and lower surfaces is much smaller than the volume resistance R at room temperature. 20℃ , that is, Rre<<R 20℃ According to the volume of this rectangular block, eight adjacent identical rectangular blocks are divided around it to derive the real-time resistance value Rt measured by the sampling controller 4. According to the premise of the local point fire source, since the eight surrounding rectangular blocks are not significantly affected by the fire source temperature, their real-time volume resistance value is still approximately equal to Rt in the normal temperature environment. 20℃ , according to Ohm's law:

[0029] Simplified, the total resistance Rt of the nine resistors in parallel near the measuring longitudinal conductor Xn and transverse conductor Yn is:

[0030] Since Rre<<R 20℃ ,therefore,

[0031] Therefore

[0032] Ignoring the wire resistance of the longitudinal conductor Xn and the transverse conductor Yn, the real-time resistance value between the longitudinal conductor Xn and the transverse conductor Yn measured by the sampling controller 4 is Rre according to the above formula. After receiving this measured value, the processor 2 can judge the temperature at the point fire source by comparing it with the preset temperature alarm threshold, thereby judging the fire alarm situation, and can locate the fire source according to the position of the measured longitudinal conductor Xn and the transverse conductor Yn, so as to realize the positioning and temperature alarm.

[0033] Similarly, when the initial fire source is a point, line, or surface fire source, the real-time resistance of the local area affected by the fire source measured by the sampling controller 4 can still represent the temperature at the fire source, thereby judging the fire alarm situation, and locating the fire source according to the position of the measured longitudinal conductor Xn and the transverse conductor Yn, thereby realizing fire source positioning and constant temperature alarm.

[0034] Obviously, as long as the data processing capability of the processor 2 is sufficient, simultaneous measurement of multiple points can be achieved. For example, the sampling controller 4 simultaneously controls the closure of the electronic switches connected to the longitudinal conductor X1, the transverse conductor Y1, the longitudinal conductor Xn, and the transverse conductor Yn. The processor 2 can simultaneously obtain the temperature data at the two intersections. By analogy, the detector of the present invention can measure the temperatures of multiple points at the same time, and can construct the temperature field distribution data on the entire sheet temperature sensitive element based on sufficient point temperature measurement values, and predict the temperature (fire) development trend through the change of the temperature field, so as to provide data support for subsequent fire fighting and rescue.

[0035] At the same time, since the temperature-sensing fire detector provided in this embodiment can collect real-time temperature data of the positioning point, the temperature rise rate of the point can be calculated by dividing the difference between the temperature data of several times before and after by the measurement time interval. When the temperature rise rate is too high and reaches the differential temperature alarm threshold, a differential temperature alarm can be issued.

[0036] At the same time, since the technology used by the temperature-sensitive fire detector provided in this embodiment is an analog detection method for real-time measurement of the resistance value near the fire source, rather than a switch detection method in which the fusible insulating layer is softened or melted by heat, resulting in a direct contact short circuit of the conductor material in the comparative technology, this embodiment can determine the physical short circuit fault condition: when the intersection of the longitudinal conductor Xn and the transverse conductor Yn is short-circuited due to physical factors such as squeezing and pulling, the real-time resistance value Rre measured by the sampling controller 4 is 0, and under normal circumstances, the resistance of the thermistor material will not decrease to 0 due to the increase in temperature. Therefore, at this time, the processor 2 determines that the intersection of the longitudinal conductor Xn and the transverse conductor Yn is a short circuit fault and alarms.

[0037] In addition, when measuring the real-time temperature of a certain positioning point in this embodiment, no external terminal resistor is required at the end of any longitudinal conductor and any transverse conductor, thereby reducing the detector fault alarm caused by damage to the external terminal resistor. Embodiment 2

[0038] In the first embodiment, the temperature is measured by the corresponding relationship between the resistance value of the negative temperature coefficient resistor material and the temperature. However, in practical applications, the linear relationship between the resistance value of the negative temperature coefficient resistor material and the temperature is required to be relatively high in order to measure the temperature more conveniently and accurately. This embodiment uses the thermocouple principle to measure the temperature, which can reduce the requirements for the linear relationship performance between the negative temperature coefficient resistor material and the temperature: The conductor groups 7 and 8 in the first embodiment are replaced with two different types of conductor materials, such as copper and iron. The sheet-shaped temperature sensitive element 6 filled between the conductors is still NTC material. Similar to the first embodiment, the sampling controller 4 controls the electronic switch connected to the longitudinal conductor X1 to close first, and then controls the electronic switch connected to the transverse conductor Y1 to close, but the difference is that the processor 2 in this embodiment measures the potential difference between the conductors X1 and Y1 at this time. When the temperature of the intersection (or vicinity) of the conductors X1 and Y1 of different material types rises due to the influence of the fire source, the resistance of the temperature sensitive material with NTC characteristics between the conductors here will decrease or even short-circuit, thereby forming a thermoelectric joint, and the temperature difference between the ends of the two conductors located in the signal processing unit 1 is basically zero, so this temperature difference between the far and near ends forms a thermocouple effect between the conductors X1 and Y1. According to the principle of the thermocouple effect, two different conductors in the same circuit will generate a voltage difference when there is a temperature difference at both ends. The real-time temperature at the intersection of X1 and Y1 can be measured by measuring the voltage difference between the corresponding conductor end positions in the switch group 5 by the processor 2. After the measurement is completed, the electronic switch connected to the transverse conductor Y1 is disconnected again, and the electronic switch connected to the transverse conductor Y2 is closed to measure the voltage difference between the longitudinal conductor X1 and the transverse conductor Y2 at the same time. This sequence is repeated until the voltage difference between the longitudinal conductor X1 and the transverse conductor Yn is measured, thereby obtaining the temperature value of the intersection between X1 and Y1, Y2...Yn. According to this rule, the temperature values ​​of all points can be measured.

[0039] This method in this embodiment draws on the measurement principle of the existing thermocouple detector (see https: / / baijiahao.baidu.com / s?id=1714958203234454707&wfr=spider&for=pc "Thermocouple, Thermoelectric Effect and Thermoelectric Effect Principle"), and does not require high accuracy of the resistance-temperature characteristic of the sheet temperature sensitive element 6, and is particularly suitable for low-cost multi-point temperature measurement on the sheet detector.

[0040] In addition, the sheet-like temperature sensitive element can also be woven or layered into a planar mesh structure by a plurality of longitudinal conductors respectively coated with temperature coefficient materials and a plurality of transverse conductors respectively coated with temperature coefficient materials. This can reduce the amount of temperature coefficient material used (equivalent to removing the temperature coefficient material outside a certain range of the intersection of the transverse and longitudinal conductors on the sheet structure). At the same time, the hollow structure is also conducive to the ventilation, heat dissipation and anti-condensation of the protected object covered by the detector. Embodiment 3

[0041] The flat sheet-like temperature sensitive element in the first or second embodiment is wound into a three-dimensional open sleeve shape, so that it can be easily wrapped around the outer surface of a power cable or a heating pipe to adapt to the three-dimensional structure of the protected object. Figure 4 The present invention is a three-dimensional perspective view of a sleeve-shaped sheet temperature sensitive element, wherein the sheet temperature sensitive element comprises a sheet body 10 formed of a negative temperature coefficient resistor material and having an approximately open sleeve shape, a radial conductor group 7' of a plurality of radial conductors X1', X2', ..., Xn' laid on the outer surface of the sheet body 10 (or embedded to a certain depth) and arranged uniformly in the axial direction, an axial conductor 8' (i.e., Y') laid on the inner surface of the sheet body 10 (or embedded to a certain depth) and evenly arranged end to end at different angles of the circumference, and a waterproof insulating protective layer 11 covering the outer sides of the sheet body 10 and the radial conductor group 7' and the axial conductor 8', wherein the projections of the radial conductor group 7' and the axial conductor 8' on the surface of the sheet body are perpendicular to each other. The various parts of the sheet-shaped temperature sensitive element are tightly stacked together through a pressing process, and the edges are sealed as a whole by means of gluing (the radial conductor group 7' and the axial conductor 8' should be appropriately extended out of the sheet body 10 for easy wiring), and finally a waterproof, moisture-proof and mechanically damage-proof sheet-shaped thermal sensitive element is formed. Its cross-sectional view is shown in FIG. Figure 5 As shown, it should be pointed out that the axial conductors 8' of this embodiment are connected end to end into one conductor in order to reduce the number of wiring, because for the protection of slender power cables or heating pipes 15, users usually only care about the length position of the fire source in the axial direction and ignore the position in the radial direction; and in order to facilitate the radial conductor group 7' to be led out to the signal processing unit and connected to the electronic switch, in this embodiment, the sheet body 10 and the waterproof insulation protection layer 11 are partially extended at the opening to cover the radial conductor group 7' that needs to be folded back. As for the working principle of the sheet temperature sensitive element shown in this embodiment, it is basically the same as the previous two embodiments, only the number of axial conductors 8' is simplified, so it will not be repeated.

[0042] The embodiments cited above are examples of preferred implementation modes of the present invention, and are not limitations on the device. Without affecting the essential conditions of the present invention, the components in the above embodiments can be changed, modified, replaced, combined, and simplified according to actual needs, all of which should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A heat-sensing fire detector, characterized in that: It is mainly composed of a sheet-like temperature sensitive element and a signal processing unit and a number of connecting wires therebetween; wherein the sheet-like temperature sensitive element includes a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistance material therebetween; the longitudinal conductor group is composed of a number of longitudinal conductors arranged in parallel at intervals; the transverse conductor group is composed of a number of transverse conductors arranged in parallel at intervals, and the number of longitudinal conductors and the transverse conductors are perpendicular to each other; the number of connecting wires includes a number of longitudinal connecting wires and a number of transverse connecting wires; the signal processing unit is mainly composed of a processor, a sampling controller, an electronic switch group and an output actuator; the electronic switch group is mainly composed of a number of longitudinal normally open electronic switches and a number of transverse normally open electronic switches; one end of the number of longitudinal conductors and one end of the number of transverse conductors are respectively connected to the number of longitudinal normally open electronic switches and the number of transverse normally open electronic switches through a number of longitudinal connecting wires and a number of transverse connecting wires, and then electrically connected to the processor through the sampling controller; the output actuator is electrically connected to the processor.

2. A heat-sensing fire detector, characterized in that: It is mainly composed of a sheet-like temperature sensitive element and a signal processing unit and a number of connecting wires therebetween; wherein the sheet-like temperature sensitive element includes a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistance material therebetween; the longitudinal conductor group is composed of a number of longitudinal conductors arranged in parallel and spaced apart; the transverse conductor group is composed of a number of transverse conductors arranged in parallel and spaced apart, and the number of longitudinal conductors and the transverse conductors are perpendicular to each other; the number of connecting wires includes a transverse connecting wire and a number of longitudinal connecting wires; the signal processing unit is mainly composed of a processor, a sampling controller, an electronic switch group and an output actuator; the electronic switch group is mainly composed of a number of longitudinal normally open electronic switches and a transverse normally open electronic switch; the left and right ends of the number of transverse conductors are spaced apart to form a serpentine transverse conductor, and one end of the number of transverse conductors is connected to the transverse normally open electronic switch through the transverse connecting wire; one end of the number of longitudinal conductors is connected to the number of longitudinal normally open electronic switches one by one through a number of longitudinal connecting wires, and then electrically connected to the processor through the sampling controller; the output actuator is electrically connected to the processor.

3. The heat-sensing fire detector according to claim 1 or 2, characterized in that: The negative temperature coefficient resistor material forms a sheet, the longitudinal conductor group and the transverse conductor group are respectively laid on the upper and lower surfaces of the sheet, and the projections of the plurality of longitudinal conductors and transverse conductors on the surface of the sheet are perpendicular to each other.

4. The heat-sensing fire detector according to claim 1 or 2, characterized in that: The negative temperature coefficient resistor material is coated outside the plurality of longitudinal conductors and / or the plurality of transverse conductors, and the plurality of longitudinal conductors and the transverse conductors are woven or layered up and down to form a mutually perpendicular mesh structure.

5. The heat-sensing fire detector according to claim 1 or 2, characterized in that: The plurality of longitudinal conductors and the plurality of transverse conductors are respectively made of two different kinds of metal materials.

6. The heat-sensing fire detector according to claim 3, characterized in that: The plurality of longitudinal conductors and the plurality of transverse conductors are respectively made of two different kinds of metal materials.

7. The heat-sensing fire detector according to claim 4, characterized in that: The plurality of longitudinal conductors and the plurality of transverse conductors are respectively made of two different kinds of metal materials.

8. The heat-sensitive fire detector according to claim 1, 2, 6 or 7, characterized in that: It is characterized in that The outer side of the sheet-shaped temperature sensitive element is also covered with a waterproof insulating protective layer.

9. The heat-sensing fire detector according to claim 3, characterized in that: The outer side of the sheet-shaped temperature sensitive element is also covered with a waterproof insulating protective layer.

10. The heat-sensing fire detector according to claim 4, characterized in that: The outer side of the sheet-shaped temperature sensitive element is also covered with a waterproof insulating protective layer.

11. The heat-sensing fire detector according to claim 5, characterized in that: The outer side of the sheet-shaped temperature sensitive element is also covered with a waterproof insulating protective layer.

12. A detection alarm method, characterized in that: The method comprises: Step 1: The sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one horizontal conductor in the sheet-like temperature sensitive element to close, and respectively measures the resistance value between the vertical conductor X1 and the horizontal conductor; Step 2: Following step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to the at least one horizontal conductor in the sheet-shaped temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one of the remaining horizontal conductors in the sheet-shaped temperature sensitive element is closed; and at the same time, the resistance value between the longitudinal conductor X1 and the longitudinal conductor X1 is measured respectively; Step 3: Follow step 2 until the resistance values ​​between the longitudinal conductor X1 in the sheet-shaped temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; Step 4: Following step 3, after a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the resistance values ​​between the vertical conductor X2 in the sheet-like temperature sensitive element and all the transverse conductors in turn using the same method as steps 1 to 3; Step 5: Following step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as steps 1 to 4 is used until the resistance values ​​between the longitudinal conductor Xn in the sheet-like temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; that is, one measurement cycle is completed; Step 6: Continue with step 5, and repeat the measurement from step 1 to step 5 over and over again; The sampling controller in steps 1 to 6 respectively measures the resistance value in real time and sends it to the processor connected thereto in real time. The processor compares the resistance value with the resistance value corresponding to the preset temperature alarm threshold in real time to determine whether it is a fire alarm, and directly outputs a fixed temperature alarm signal through the output actuator connected to the processor, or calculates whether the temperature change rate per unit time reaches the preset differential temperature alarm threshold, and the output actuator outputs a differential temperature alarm signal; The sheet-shaped temperature sensitive element comprises a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistor material therebetween, wherein the longitudinal conductor group is composed of a plurality of longitudinal conductors X1, X3, ..., Xn which are fixedly spaced and parallel, and the transverse conductor group is composed of a plurality of transverse conductors Y1, Y2, ..., Yn which are fixedly spaced and parallel, and the projections of the plurality of longitudinal conductors and the transverse conductors on the surface of the sheet-shaped body are perpendicular to each other; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a plurality of transverse normally-open electronic switches; one end of the plurality of longitudinal conductors and one end of the plurality of transverse conductors are connected to the plurality of longitudinal normally-open electronic switches and the plurality of transverse normally-open electronic switches in a one-to-one correspondence through a plurality of longitudinal connecting wires and a plurality of transverse connecting wires, respectively.

13. The detection alarm method according to claim 12, characterized in that: The step 1: the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-like temperature sensitive element to close and measure the resistance value between the vertical conductor X1 and the horizontal conductor Y1; The step 2 is as follows from the step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-like temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y2 in the sheet-like temperature sensitive element is closed; and the resistance value between the longitudinal conductor X1 and the horizontal conductor Y2 is measured at the same time; Step 3: Following step 2, the transverse conductors Y3, ..., Yn in the sheet-like temperature sensitive element are measured in sequence, until the resistance value between the longitudinal conductor X1 and the transverse conductor Yn in the sheet-like temperature sensitive element is measured; The step 4 is as follows from the step 3. After a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the resistance values ​​between the vertical conductor X2 and the horizontal conductors Y1, Y2, ..., Yn in the sheet-like temperature sensitive element in the same manner as the steps 1 to 3; The step 5: following the step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as the steps 1 to 4 is used until the resistance value between the longitudinal conductor Xn and the transverse conductors Y1, Y2, ..., Yn in the sheet-like temperature sensitive element is measured; that is, one measurement cycle is completed; The step 6 is followed by the step 5, and the steps 1 to 5 are repeated and measured over and over again.

14. The detection alarm method according to claim 13, characterized in that: In the steps 1, 2 and 3, the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-shaped temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to a serpentine horizontal conductor in the sheet-shaped temperature sensitive element to close and measure the resistance value between the vertical conductor X1 and the serpentine horizontal conductor; The step 4 is as follows from the steps 1, 2 and 3. After a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the resistance value between the vertical conductor X2 in the sheet-like temperature sensitive element and the serpentine transverse conductor in turn respectively by the same method as the steps 1, 2 and 3; The step 5: following the step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, using the same method as the steps 1, 2 and 3 to step 4 until the resistance value between the longitudinal conductor Xn in the sheet-like temperature sensitive element and the serpentine transverse conductor is measured; that is, one measurement cycle is completed; Step 6: Continuing from step 5, repeat the measurement from steps 1, 2 and 3 to step 5, and repeat the process over and over again; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a transverse normally-open electronic switch; the serpentine transverse conductor is composed of a plurality of transverse conductors whose left and right ends are connected at intervals, and one end of the serpentine transverse conductor is connected to the transverse normally-open electronic switch through the transverse connecting wire; one end of the plurality of longitudinal conductors is respectively connected to the plurality of longitudinal normally-open electronic switches one by one through a plurality of longitudinal connecting wires.

15. A detection alarm method, characterized in that: The method comprises: Step 1: The sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one horizontal conductor in the sheet-like temperature sensitive element to close and respectively measure the voltage value between the vertical conductor X1 and it; Step 2: Following step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one horizontal conductor in the sheet-shaped temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to at least one of the remaining horizontal conductors in the sheet-shaped temperature sensitive element is closed; and at the same time, the voltage value between the longitudinal conductor X1 and it is measured respectively; Step 3: Follow step 2 until the voltage values ​​between the longitudinal conductor X1 in the sheet-shaped temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; Step 4: Following step 3, after a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the voltage values ​​between the vertical conductor X2 in the sheet-like temperature sensitive element and all the transverse conductors in turn using the same method as steps 1 to 3; Step 5: Following step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as steps 1 to 4 is used until the voltage values ​​between the longitudinal conductor Xn in the sheet-like temperature sensitive element and all the transverse conductors Y1, Y2, ..., Yn are measured respectively; that is, one measurement cycle is completed; Step 6: Continue with step 5, and repeat the measurement from step 1 to step 5 over and over again; The sampling controller in steps 1 to 6 respectively measures the voltage value in real time and sends it to the processor connected thereto in real time. The processor compares its resistance value with the voltage value corresponding to the preset temperature alarm threshold in real time to determine whether it is a fire alarm, and directly outputs a fixed temperature alarm signal through the output actuator connected to the processor, or calculates whether the temperature change rate per unit time reaches the preset differential temperature alarm threshold, and the output actuator outputs a differential temperature alarm signal; The sheet-shaped temperature sensitive element comprises a longitudinal conductor group, a transverse conductor group and a negative temperature coefficient resistor material therebetween, the longitudinal conductor group is composed of a plurality of longitudinal conductors X1, X3, ..., Xn which are fixedly spaced and parallel, the transverse conductor group is composed of a plurality of transverse conductors Y1, Y2, ..., Yn which are fixedly spaced and parallel, and the projections of the plurality of longitudinal conductors and the transverse conductors on the surface of the sheet body are perpendicular to each other; the plurality of longitudinal conductors X1, X3, ..., Xn and the plurality of transverse conductors Y1, Y2, ..., Yn are respectively made of two different kinds of metal materials; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a plurality of transverse normally-open electronic switches; one end of the plurality of longitudinal conductors and one end of the plurality of transverse conductors are connected to the plurality of longitudinal normally-open electronic switches and the plurality of transverse normally-open electronic switches in a one-to-one correspondence through a plurality of longitudinal connecting wires and a plurality of transverse connecting wires, respectively.

16. The detection alarm method according to claim 15, characterized in that: In step 1, the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-shaped temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-shaped temperature sensitive element to close and measure the voltage value between the vertical conductor X1 and the horizontal conductor Y1; The step 2 is as follows from the step 1, after a preset time interval, the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y1 in the sheet-like temperature sensitive element is disconnected again, and the corresponding horizontal normally open electronic switch in the electronic switch group connected to the horizontal conductor Y2 in the sheet-like temperature sensitive element is closed; and the voltage value between the longitudinal conductor X1 and the horizontal conductor Y2 is measured at the same time; The step 3: following the step 2, the transverse conductors Y3, ..., Yn in the sheet-like temperature sensitive element are measured in sequence, until the voltage value between the longitudinal conductor X1 and the transverse conductor Yn in the sheet-like temperature sensitive element is measured; The step 4 is as follows from the step 3. After a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the voltage values ​​between the vertical conductor X2 in the sheet-like temperature sensitive element and the horizontal conductors Y1, Y2, ..., Yn in turn respectively by using the same method as the steps 1 to 3; Step 5: Following step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, and the same method as steps 1 to 4 is used until the voltage value between the longitudinal conductor Xn and the transverse conductors Y1, Y2, ..., Yn in the sheet-like temperature sensitive element is measured; that is, one measurement cycle is completed; The step 6 is followed by the step 5, and the steps 1 to 5 are repeated and measured over and over again.

17. The detection alarm method according to claim 16, characterized in that: In the steps 1, 2 and 3, the sampling controller first controls the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element to close, and then controls the corresponding horizontal normally open electronic switch in the electronic switch group connected to a serpentine horizontal conductor in the sheet-like temperature sensitive element to close and measure the voltage value between the vertical conductor X1 and the serpentine horizontal conductor; The step 4 is as follows: following the steps 1, 2 and 3, after a preset time interval, the sampling controller disconnects the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X1 in the sheet-like temperature sensitive element and closes the corresponding vertical normally open electronic switch in the electronic switch group connected to the vertical conductor X2 in the sheet-like temperature sensitive element, and measures the voltage value between the vertical conductor X2 in the sheet-like temperature sensitive element and the serpentine transverse conductor in turn respectively by the same method as the steps 1, 2 and 3; The step 5: following the step 4, the longitudinal conductors X3, ..., Xn in the sheet-like temperature sensitive element are measured in sequence, using the same method as the steps 1, 2 and 3 to step 4 until the voltage value between the longitudinal conductor Xn in the sheet-like temperature sensitive element and the serpentine transverse conductor is measured; that is, one measurement cycle is completed; Step 6: Continuing from step 5, repeat the measurement from steps 1, 2 and 3 to step 5, and repeat the process over and over again; The electronic switch group is mainly composed of a plurality of longitudinal normally-open electronic switches and a transverse normally-open electronic switch; the serpentine transverse conductor is composed of a plurality of transverse conductors whose left and right ends are connected at intervals, and one end of the serpentine transverse conductor is connected to the transverse normally-open electronic switch through the transverse connecting wire; one end of the plurality of longitudinal conductors is respectively connected to the plurality of longitudinal normally-open electronic switches one by one through a plurality of longitudinal connecting wires.

18. The detection alarm method according to claim 12 or 13 or 14 or 15 or 16 or 17, characterized in that: The sheet is made of negative temperature coefficient resistor material, the longitudinal conductor group and the transverse conductor group are respectively laid on the upper and lower surfaces of the sheet, and the projections of the plurality of longitudinal conductors and transverse conductors on the surface of the sheet are perpendicular to each other.

19. The detection alarm method according to claim 12 or 13 or 14 or 15 or 16 or 17, characterized in that: The negative temperature coefficient resistor material is coated outside the plurality of longitudinal conductors and / or the plurality of transverse conductors, and the plurality of longitudinal conductors and the transverse conductors are woven or layered up and down to form a mutually perpendicular mesh structure.

20. The detection alarm method according to claim 12 or 13 or 14 or 15 or 16 or 17, characterized in that: The outer sides of the longitudinal conductor group and the transverse conductor group are also covered with a waterproof insulating protective layer.

21. The detection alarm method according to claim 18, characterized in that: The outer sides of the longitudinal conductor group and the transverse conductor group are also covered with a waterproof insulating protective layer.

22. The detection alarm method according to claim 19, characterized in that: The outer sides of the longitudinal conductor group and the transverse conductor group are also covered with a waterproof insulating protective layer.

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